package pers.study.binarysearch;

/**
 * @author rookie
 * @date 2020/4/12
 */
public class BinarySearch {
    public static int rank(int key, int[] a){
        int lo = 0;
        int hi = a.length - 1;
        while (lo < hi){
            int mid = lo + (hi - lo) / 2;
            if (key < a[mid]) {
                hi = mid - 1;
            } else if (key > a[mid]) {
                lo = mid +1;
            } else {
                return mid;
            }
        }
        return -1;
    }
}
